IMAGINE your arteries and their delicate, branching capillaries growing narrow and stiff–a consequence of inactivity, stress, being overweight, and diet consisting of fatty and sweet food. Inside, unseen and unfelt, your blood hurtles along like a river squeezed into a ravine, banging so forcefully against artery walls that it can injure and weaken them. Ultimately, this pressure can rapture blood vessels in the brain (causing a stroke) or the abdomen (causing an abdominal aortic aneurysm). It can cause the heart muscle to enlarge and weaken, and is a powerful promoter of atherosclerosis in the coronary arteries, the precursor to heart attack.
High blood pressure (hypertension) is recognized as the greatest of cardiovascular risk factors and, because it is initially largely symptomless, had often been dubbed the “silent killer.” Today millions of people have high blood pressure. The condition is less common in younger adults but more common in people of Afro-Caribbean origin and from the Indian sub-continent. Most people with high blood pressure – just under 80 percent of men and 70 percent of women – do not receive treatment. Of those who are treated, more than 60 percent remain hypertensive.
The odds are a staggering 90 percent that you’ll develop high blood pressure sooner or later–whether you’re a man or a woman.
While men under 55 are more likely than women to have high blood pressure, once women reach 55 they tend to catch up with, and even overtake, the men.
Hypertension occurs when arterioles–the small thin-walled branches of an artery become stiff and inflexible and cause hypertension by increasing resistance to the blood flow. High blood pressure in turn damages artery walls, making them more vulnerable to plaque build up. It also weakens and enlarges the heart.
Genetics may account for 30 percent of cases of hypertension. For the rest of us, it’s a combination of higher-than-normal fluid content in the bloodstream, due most often to an excessively salty diets plus narrower, stiffer arteries–the result of atherosclerosis, inactivity, overweight, chronic stress and/or diabetes. Evidence from 61 blood pressure studies suggests that risks of fatal heart disease and stroke may begin when blood pressure is as low as 115/75. Risk doubles with each 20-point rise in the first number in a reading (systolic pressure) and each 10-point rise in the second number (diastolic pressure).
Blood pressure measures the force of blood against artery walls while the heart is contracting at full force and while it’s resting between beats. You can have your blood pressure checked regularly.
BLOOD PRESSURE
(mm/hg)
Below 120/80
120-129/80-85
130-139/85-89
140-159/90-99
160-179/100-109
160/110 and above
Digital blood pressure monitors are gradually replacing the most widely used method of checking blood pressure, in which a doctor or nurse straps a black cuff to your arm, applies a stethoscope, pumps up the cuff until it cuts of blood flow, and measures the results as pressure is released. High blood pressure usually has no symptoms that you can feel or see.
Researchers are now beginning to understand precisely how modern life and genetics team up to cause high blood pressure.
Your heart. The harder it has to work, the happier it is and the healthier you will be. The transient rise in blood pressure when you exercise is quite normal and healthy, unless you already have high blood pressure or atherosclerosis. But unrelenting stress–hourly, day in day out puts constant pressure on your arteries and causes damage.
Your arteries. Your arteries are lined with smooth muscle that can expand or contract as blood flows through. The more elastic your arteries, the less resistant they are to the flow of blood and the less the force that’s exerted on their walls. But if your arteries are clogged with plaque, your blood pressure will rise as blood is forced through a narrower channel.
Your kidneys. They control how much sodium your body contains and thus how much water stays in your blood (sodium retains water). More water means more fluid trying to get through the blood vessels – and higher blood pressure.
Your hormones. So-called stress hormones make the heart beat faster and the arteries narrow, which raises blood pressure. Other hormones regulate blood pressure; drugs known as ACE inhibitors lower blood pressure by controlling these hormones.
Act now
While high blood pressure is a known killer–it plays a role in 75 percent of all heart attacks and strokes, a third of people with hypertension don’t know they have it. Others know they’ve got it but don’t have it under control.
Doctors are not ignoring the potential risk of high blood pressure. Lower is better. Damage to arteries actually begins at blood pressure levels that doctors have previously considered optimal. The British Hypertension Society recommends that, in general, people with a systolic blood pressure consistently above 160mmHg and/or a diastolic pressure over 100mmHg need treatment to lower their blood pressure.
Perhaps the least mysterious thing about blood pressure is this: self-help measures can work and may help you avoid having to take diuretics or other BP lowering drugs. Even if you are taking medication, healthy lifestyle changes are worthwhile. From proven, practical steps (losing weight cuts blood pressure significantly, as does limiting salt) to mental relaxation techniques, meditation, there are many small daily changes that can lower blood pressure.
Losing just 10 percent of your body weight could lower your high blood pressure down to a normal range, without drugs. So could a diet rich in fruit and vegetables. And try to avoid taking too many nonsteroidal anti-inflammatory drugs. Studies have shown that regular consumption of these painkillers can also raise hypertension risk.
